diff --git a/src/blenderbim/blenderbim/bim/module/model/product.py b/src/blenderbim/blenderbim/bim/module/model/product.py
index 2904c8d2ca..f9c8d28a7d 100644
--- a/src/blenderbim/blenderbim/bim/module/model/product.py
+++ b/src/blenderbim/blenderbim/bim/module/model/product.py
@@ -113,7 +113,6 @@ class AddConstrTypeInstance(bpy.types.Operator):
     bl_label = "Add"
     bl_options = {"REGISTER", "UNDO"}
     bl_description = "Add Type Instance to the model"
-    ifc_class: bpy.props.StringProperty()
     relating_type_id: bpy.props.IntProperty()
     from_invoke: bpy.props.BoolProperty(default=False)
 
@@ -232,15 +231,13 @@ class AddConstrTypeInstance(bpy.types.Operator):
                 bpy.ops.bim.add_filled_opening(voided_obj=building_obj.name, filling_obj=obj.name)
         else:
             if collection_obj and tool.Ifc.get_entity(collection_obj):
-                obj.location[2] = collection_obj.location[2] - min([v[2] for v in obj.bound_box])
+                obj.location.z = collection_obj.location.z - tool.Blender.get_object_bounding_box(obj)["min_z"]
 
         unit_scale = ifcopenshell.util.unit.calculate_unit_scale(tool.Ifc.get())
         for port in ifcopenshell.util.system.get_ports(relating_type):
-            mat = ifcopenshell.util.placement.get_local_placement(port.ObjectPlacement)
-            mat[0][3] *= unit_scale
-            mat[1][3] *= unit_scale
-            mat[2][3] *= unit_scale
-            mat = obj.matrix_world @ mathutils.Matrix(mat)
+            mat = Matrix(ifcopenshell.util.placement.get_local_placement(port.ObjectPlacement))
+            mat.translation *= unit_scale
+            mat = obj.matrix_world @ mat
             new_port = tool.Ifc.run("root.create_entity", ifc_class="IfcDistributionPort")
             tool.Ifc.run("system.assign_port", element=element, port=new_port)
             tool.Ifc.run("geometry.edit_object_placement", product=new_port, matrix=mat, is_si=True)
diff --git a/src/blenderbim/blenderbim/bim/module/model/ui.py b/src/blenderbim/blenderbim/bim/module/model/ui.py
index b559b8ae78..9ff0b0a282 100644
--- a/src/blenderbim/blenderbim/bim/module/model/ui.py
+++ b/src/blenderbim/blenderbim/bim/module/model/ui.py
@@ -125,7 +125,6 @@ class LaunchTypeManager(bpy.types.Operator):
             text = f"Add {relating_type['predefined_type']}" if relating_type["predefined_type"] else "Add"
             op = row.operator("bim.add_constr_type_instance", icon="ADD", text=text)
             op.from_invoke = True
-            op.ifc_class = relating_type["ifc_class"]
             op.relating_type_id = relating_type["id"]
 
             op = row.operator("bim.rename_type", icon="GREASEPENCIL", text="")
diff --git a/src/blenderbim/blenderbim/bim/module/model/workspace.py b/src/blenderbim/blenderbim/bim/module/model/workspace.py
index 1434c68e4f..94d6137cd2 100644
--- a/src/blenderbim/blenderbim/bim/module/model/workspace.py
+++ b/src/blenderbim/blenderbim/bim/module/model/workspace.py
@@ -411,7 +411,6 @@ class BimToolUI:
             row.label(text="", icon="EVENT_A")
             op = row.operator("bim.add_constr_type_instance", text="Add")
             op.from_invoke = True
-            op.ifc_class = cls.props.ifc_class
             if cls.props.relating_type_id.isnumeric():
                 op.relating_type_id = int(cls.props.relating_type_id)
 
@@ -463,7 +462,6 @@ class BimToolUI:
             row.label(text="", icon="EVENT_A")
             op = row.operator("bim.add_constr_type_instance", text="Add")
             op.from_invoke = True
-            op.ifc_class = cls.props.ifc_class
             if cls.props.relating_type_id.isnumeric():
                 op.relating_type_id = int(cls.props.relating_type_id)
 
diff --git a/src/blenderbim/test/bim/test_feature.py b/src/blenderbim/test/bim/test_feature.py
index 8fcc687c2d..050eeeb229 100644
--- a/src/blenderbim/test/bim/test_feature.py
+++ b/src/blenderbim/test/bim/test_feature.py
@@ -754,7 +754,7 @@ def i_display_the_construction_type_browser():
 @when("I add the construction type")
 def i_add_the_active_construction_type():
     props = bpy.context.scene.BIMModelProperties
-    bpy.ops.bim.add_constr_type_instance(ifc_class=props.ifc_class, relating_type_id=int(props.relating_type_id))
+    bpy.ops.bim.add_constr_type_instance(relating_type_id=int(props.relating_type_id))
 
 
 @then(parsers.parse("construction type is {relating_type_name}"))